A green sea turtle gets algae removed from his shell a smaller cleaner
fish which otherwise would slow him down (Hawaii).

Symbiosis between a shrimp and a Goby. They both live together in
the same burrow dug by shrimp. The shrimp benefits from this symbiosis
because the Goby stays on the lookout for predators. So before the shrimp
dares to come out of the burrow, he makes contact with his antennae
with the Goby who gives him a signal with his fins whether or not it
is safe to come out. The Goby benefits because he has someone to provide
a hiding place and who continuously digs up food animals from the sand
(Philippines).

There are many different species of Gobies who all live
together with their particular species of shrimp (Philippines).